Congress spokesperson Randeep Singh Surjewala said he is not ruling out "foul play" in the malfunction of the flight carrying Congress President Rahul Gandhi and his aides to Hubli in Karnataka Thursday morning.

Rahul Gandhi is in the thick of campaigning for the upcoming Karnataka Legislative Assembly election scheduled for 12 May, 2018 where chief minister Siddaramaiah is up against BJP's pick BS Yeddyurappa for the state's top job.

File image of Congress president Rahul Gandhi. PTI

"At around 10:45 am, the flight nosedived accompanied by loud sounds, it shuddered and then lost contact with the radar. The way it shook and swayed and narrowly escaped...we cannot rule out the possibility of foul play at this moment. A thorough investigation is absolutely essential", Surjewala said.

Rahul Gandhi, his aides Kaushal Vidyarthee, Rampreet, Rahul Ravi and SGP official Rahul Gautam were flying from New Delhi to Hubli in a special flight (VT-AVH) in "sunny and normal" conditions, according to an official compliant that the Congress has filed after a "narrow escape".

"Never thought we would make it through what happened in the aircraft today...cant believe how brave RG is...being a pilot himself he was constantly by the side of the crew through the crisis. Respect!", tweeted Rahul Ravi, who was on the same flight to Hubli with Rahul Gandhi.

Rahul Gandhi's aide Kaushal Vidyarthee, in a written complaint to Karnataka Director General of Police and Inspector General of Police Neelamani N. Raju, has demanded an investigation into the flight malfunction and asked that the aircraft be grounded till the investigation is complete.

"The flight, which took off from New Delhi around 9:20 a.m., faced unexpected technical errors. At around 10: 45 a.m. the flight suddenly tilted heavily on the left side and the altitude dipped steeply, combined with the violent shuddering of the aircraft body. It is to be stated that the weather outside was sunny, normal and not windy as per observation of the passengers and as per the forecast for the day", the complaint reads.

"It was also learnt that the autopilot of the aircraft was not functioning. After two attempts, the plane finally landed at Hubli around 11:25 a.m. while continuously shaking and making unusual audible sounds. Serious questions related to intentional tampering with the aircraft cannot also be brushed aside and are required to be addressed and investigated," says the complaint.

Kaushal Vidyarthee, travelling in Special Flight New Delhi-Hubli, with 4 others including Rahul Gandhi, writes to DG&IG K'taka stating 'unexplained technical failures' occurred during course of flight; also adds 'shuddering & altitude dipping were not natural or weather related'. pic.twitter.com/XeVLN0syXi